Thread-rolling tool



May 30, 1944- A. w. HALLBERG 2,349,862

THREAD-ROLLING TOOL May 30, 1944. A. w. HALLBERG THREAD-ROLLING TOOL Filed .my 2s, 1942 4 sheets-Sheet 3 May 30, 1944 A. w. HALLBERG 2,349,862

THREAD-ROLLING TOOL Filed July 29, 1942 4 Sheets-Sheet 4 Patented May 30, 1944 THREAD-ROLLING TOOL August W.4 Hallberg,.Waterbury, Conn., assigner to Chase Brass 8.: Copper Co. Incorporated, Waterbury; Conn., a corporation Application July29,- 1942, Serial No. 452,721

(CLSll-Bl 2 Claims;

This invention relates to improvements in thread-rolling tools.

One object of this invention is to'provide' an improved portable thread-rolling tool which may be readily employed in the field. 6 The work-holder 28 in the particular form oi' Another object of this invention is tofprovide the invention illustrated is of longitudinally-split an improved thread-rolling tool formed of simple form and has two separate parts 2l and 22 each elements readily manufactured and readily asprovided with an approximately semicylindricalsembled toy produce an eilicient constructionrat groove or channel 26 so that when the two parts minimum cost. or halves 2l and 22 are assembled together in With the above and other objects in view,.as clamping relation with the dowel-pins 2l and will. appear to those skilled in the art` from the` doWel-pin holes 28 in telescoped engagement. the present disclosure, this invention includes all fea'- two semicylindrical grooves or channels 26 t0- tures in the said disclosure which are novel over gether form an approximately-cylindrical hole the prior art. fora pipe or tube 29 to be gripped therein by -the In the accompanying drawings, in-which one parts or jaws 2l and 22, with an end-portion of wayof carrying out the inventionis shown'for the tube 29 extending beyond the end-portion illustrative purposes: 30 of the work-holder 2D which has the external Fig. 1 is a top plan view illustrating one emlead-screw thread-portions 3| which together bodiment of the invention; form-the external leed-screw thread of the work- Fig..2 is a front elevation of Fig..1 illustrating holder 20. the threading operation being performed while The threading-head `includes a body-memthe Work-holder is held clampedina vise; ber 32 which has three arbors or shafts 33 iixedly Fig. 3 is an enlarged sectional View on line secured in the body-member 32 by means of set- 3-3 ofFig. 1; 25 screws 34, the arbors 33 having freely rotatably Fig. 4 is a sectional view on line 4-4-0fFig. 3; mounted thereon the three thread-rolling rolls 35 Fig. 5 is a, sectional view on line-Es-Sof Fig. 3: preferablyl of hardened steel. In the particular Fig. 6 is a sectional view `on line G-Gof Fig. 3; formv of` the invention illustrated, the threading- F'ig. 7 is a view similar to Fig. 1 of theiholder head 25 has the internal lead-screw thread 36 forthe threading-head; formed in a separate sleeve 3l instead of being Fig. 8 is a front elevation of the body-member of the threading-head;

Fig. 9 is a top plan view of Fig. 8;

Fig. 10 is a top plan view of the sleeve which is adapted to be secured in the threading-head body-member shown in Fig. 8, which sleeve is provided With an internal lead-screw thread;

Fig. 11 is a sectional view on line II-II of Fig. 10;

Fig. 12 is a perspective view of one of the thread-rolling rolls;

Fig. 13 is a perspective view of one-half of the Work-holder:

Fig. 14 is a perspective view of the other half of the Work-holder; and

Fig. 15 is a view partly in section of a tube which has been threaded by the tool of the present invention.

In the description and claims. the various parts and steps are identied by specic names for convenience. but they are intended to be as generic in their application as the prior art will permit.

The particular thread-rolling tool chosen for illustrating the present invention includes a work-holder 2U`formed of two half-parts 2l and 22 and a thread-rolling unit 23 which includes a threading-head holder 24 and a threadinghead 25.

formed directly in the body-member 32 itself. the sleeve 31 having notches 38 to clear the inner ends of the arbors 33 and having a hole 39 alignable with a hole 40 in the body-member'32. through which a locking-screw 4l may extend to lock the sleeve 31, the body-member 32 and the threading-head holder 24 together.

A mandrel 42 has a smooth cylindrical surface 43 adapted to fit inside of a tube to be threaded and support the tube-wall against the pressure of the thread-rolling rolls 35 during the threadrolling operation, the mandrel 42 having a screwthreaded shank 44 which screw-threadedly engages in a screw-threaded opening 45 in the bodymember 32 of the threading-head 25 and is securely locked in any desired adjusted position by means of a locking-nut 46. Slots 4l and 48 in opposite ends of the mandrel 42 serve for adjusting the mandrel from either end.

Each thread-rolling roll 35 has its thread-rolling surface formed by three annular V-shaped thread-rolling ribs 49 of the same outside diameter, and one smaller diametered thread-rolling rib 50 which starts or initiates the thread-rolllng operation upon the outer surface of the tube,

the formation of a thread upon the tube being accomplished by the annular V-shaped ribs 49 and 50, by virtue of the thread-rolling rolls 35 having their axes arranged somewhat askew, as is shown in Fig. 6, so as to have the inclination of the thread-rolling ribs correspond to the 1nclination of the thread to be rolled, and by virtue of the thread-rolling rolls being forced axially of the tube by virtue of the lead-screw threads 3l and 36.

In order to perform the threading operation upon a tube 29, the tube is placed in the hole formed by the semi-cylindrical grooves 26 of the work-holder portions or halves 2| and 22 with a portion of the tube to be threaded extending beyond the end-portions 30 of the work-holder 20, as is best illustrated in Fig. 3, and the workholder halves 2| and 22 are thereupon clamped in any suitable holding device such as the jaws 5I of a vise as shown in Fig. 2, and the internal lead-screw thread 36 of the threading-head 25 is thereupon started upon the external lead-screw thread 3| formed upon the projections 30 of the work-holder 2li, and the thread-rolling unit 23 is rotated by means of the handles or hand-grips 52 of the holder 24 which causes the mandrel 42 to pass inside of and support the inner surface ofthe tube to be threaded, and also causes the thread-rolling rolls 35 to travel in a helical path and roll the threads 53 upon the external surface of the tube 29 in the manner best illustrated in Figs. 3, 4, 6 and 15. It will be noted that in rolling the threads upon the tube, the outside diameter across the threads becomes substantially greater than the outside diameter of the tubeportion from which the threads were rolled, owing to the fact that no metal is cut oil but the metal is forced to flow more or less radially outward in forming the screw-threadst. Thus, will be seen that this mode of forming screwthreads is especially applicable to thin-walled tubes such, for example, as copper or copperbase-alloy tubes which can be comparatively thin. By merely rotating the thread-rolling unit 23 in the reverse or unthreadlng direction, the unit 23 can be readily removed from the workholder 20, which latter can be removed from the vise-jaws 5i and the parts 2l and 22 of the work-holder can be readily spread apart and the threaded tube removed therefrom.

The invention may be carried out in other specific ways than those herein set forth without departing from the spirit and essential characteristics of the invention. and the present embodiments are, therefore, to be considered in all respects as illustrative and not restrictive, and all changes coming Within the meaning and equivalency range of the appended claims are intended to be embraced therein.

I claim:

1. A thread-rolling tool comprising: a longitudinally-split work-holder having opposite clamp-faces and an external lead-screw thread on its split forward end-portion, and having a hole extending through the work-holder along said longitudinal split and through said Workholder end-portion, said work-holder being adapted to securely hold a tube in said hole with an end-portion of the tube to be threaded projecting forwardly beyond said work-holder endportion; and a threading-head having an internal lead-screw thread adapted to thread upon said external lead-screw thread, and having thread-rolling means adapted to roll threads on said projecting end-portion of a tube held in said work-holder when said threading-head is ro- 4tated relatively to said work-holder to cause said internal lead-screw thread to thread upon said external lead-screw thread.

2. A thread-rolling tool ocomprising: a longitudinally-split work-holder having an external lead-screw thread on its split forward end-portion, and having a hole extending through the work-holder along said longitudinal split and through said work-holder end-portion, said work-holder being adapted to securely hold a tube in said hole with an end-portion of the tube to be threaded projecting forwardly beyond said work-holder end-portion; and a threadinghead having an internal lead-screw thread adapted to thread upon said external lead-screw thread, and having thread-rolling means adapted to roll threads on said projecting end-portion of a tube held in said work-holder when said threading-head is rotated relatively to said work-holder to cause said internal lead-screw thread to thread upon said external lead-screw thread; said longitudinally-split work-holder being adapted to be clamped in a vise, and when so clamped, acting both to clamp the tube to be threaded and a hold the work-holder in position to receive the threading-head during the threadrolling operation.

AUGUST W. HALLBERG. 

